ssl时如何忽略证书检查

我正在尝试找到一种在请求Https资源时忽略证书检查的方法，到目前为止，我在Internet上找到了一些有用的文章。

但是我仍然有一些问题。请检查我的代码。我只是不明白代码ServicePointManager.ServerCertificateValidationCallback是什么意思。

什么时候调用此委托方法？还有一个问题，我应该在哪里写这段代码？在ServicePointManager.ServerCertificateValidationCallback执行之前还是之前Stream stream = request.GetRequestStream()？

public HttpWebRequest GetRequest()
{
    CookieContainer cookieContainer = new CookieContainer();

    // Create a request to the server
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(_remoteUrl);

    #region Set request parameters

    request.Method = _context.Request.HttpMethod;
    request.UserAgent = _context.Request.UserAgent;
    request.KeepAlive = true;
    request.CookieContainer = cookieContainer;
    request.PreAuthenticate = true;
    request.AllowAutoRedirect = false;

    #endregion

    // For POST, write the post data extracted from the incoming request
    if (request.Method == "POST")
    {
        Stream clientStream = _context.Request.InputStream;
        request.ContentType = _context.Request.ContentType;
        request.ContentLength = clientStream.Length;

        ServicePointManager.ServerCertificateValidationCallback = delegate(
            Object obj, X509Certificate certificate, X509Chain chain, 
            SslPolicyErrors errors)
            {
                return (true);
            };

            Stream stream = request.GetRequestStream();

            ....
        }

        ....

        return request;
    }
}   

由于只有一个全局ServicePointManager，因此设置ServicePointManager.ServerCertificateValidationCallback将产生以下结果：所有后续请求都将继承此策略。由于它是全局“设置”，因此最好在Global.asax的Application_Start方法中进行设置。

设置回调将覆盖默认行为，您可以自己创建自定义验证例程。

对于有兴趣按每个请求应用此解决方案的任何人，这是一个选择，并使用Lambda表达式。同样的Lambda表达式也可以应用于blak3r提到的全局过滤器。此方法似乎需要.NET 4.5。

String url = "https://www.stackoverflow.com";
HttpWebRequest request = HttpWebRequest.CreateHttp(url);
request.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;

在.NET 4.0中，Lambda表达式可以这样应用于全局过滤器

ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;

这对我有用：

System.Net.ServicePointManager.ServerCertificateValidationCallback +=
delegate(object sender, System.Security.Cryptography.X509Certificates.X509Certificate certificate,
                        System.Security.Cryptography.X509Certificates.X509Chain chain,
                        System.Net.Security.SslPolicyErrors sslPolicyErrors)
    {
        return true; // **** Always accept
    };

此处的摘录：http : //www.west-wind.com/weblog/posts/2011/Feb/11/HttpWebRequest-and-Ignoring-SSL-Certificate-Errors

还有一个简短的委托解决方案：

ServicePointManager.ServerCertificateValidationCallback = delegate { return true; }; 

有人提到，在.NET 4.5之前，访问它的请求上的属性ServicePointManager不可用。

这是.NET 4.0代码，可让您ServicePoint根据每个请求进行访问。它没有使您可以访问每个请求的回调，但是应该可以让您找到有关该问题的更多详细信息。只需访问scvPoint.Certificate（或ClientCertificate如果您愿意）属性。

WebRequest request = WebRequest.Create(uri);

// oddity: these two .Address values are not necessarily the same!
//  The service point appears to be related to the .Host, not the Uri itself.
//  So, check the .Host vlaues before fussing in the debugger.
//
ServicePoint svcPoint = ServicePointManager.FindServicePoint(uri);
if (null != svcPoint)
{
    if (!request.RequestUri.Host.Equals(svcPoint.Address.Host, StringComparison.OrdinalIgnoreCase))
    {
        Debug.WriteLine(".Address              == " + request.RequestUri.ToString());
        Debug.WriteLine(".ServicePoint.Address == " + svcPoint.Address.ToString());
    }
    Debug.WriteLine(".IssuerName           == " + svcPoint.Certificate.GetIssuerName());
}

顺便说一句，这是在我知道的给定应用程序中关闭所有证书验证的最不冗长的方法：

ServicePointManager.ServerCertificateValidationCallback = (a, b, c, d) => true;

您可以在HttpClient的本地实例上设置回调，而不是向ServicePointManager添加回调以全局替代证书验证。此方法应仅影响使用该HttpClient实例进行的调用。

以下示例代码显示了如何在Web API控制器中实现忽略特定服务器的证书验证错误。

using System.Net.Http;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;

public class MyController : ApiController
{

    // use this HttpClient instance when making calls that need cert errors suppressed
    private static readonly HttpClient httpClient;

    static MyController()
    {
        // create a separate handler for use in this controller
        var handler = new HttpClientHandler();

        // add a custom certificate validation callback to the handler
        handler.ServerCertificateCustomValidationCallback = ((sender, cert, chain, errors) => ValidateCert(sender, cert, chain, errors));

        // create an HttpClient that will use the handler
        httpClient = new HttpClient(handler);
    }

    protected static ValidateCert(object sender, X509Certificate cert, X509Chain chain, SslPolicyErrors errors)
    {

        // set a list of servers for which cert validation errors will be ignored
        var overrideCerts = new string[]
        {
            "myproblemserver",
            "someotherserver",
            "localhost"
        };

        // if the server is in the override list, then ignore any validation errors
        var serverName = cert.Subject.ToLower();
        if (overrideCerts.Any(overrideName => serverName.Contains(overrideName))) return true;

        // otherwise use the standard validation results
        return errors == SslPolicyErrors.None;
    }

}

根据亚当的回答和罗布的评论，我使用了以下方法：

ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => certificate.Issuer == "CN=localhost";

过滤掉“忽略”。当然，可以根据需要添加其他发行人。由于我们需要支持一些旧代码，因此已在.NET 2.0中进行了测试。

CA5386：漏洞分析工具将提醒您这些代码。

正确的代码：

ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) =>
{
   return (sslPolicyErrors & SslPolicyErrors.RemoteCertificateNotAvailable) != SslPolicyErrors.RemoteCertificateNotAvailable;
};

对于.net core

using (var handler = new HttpClientHandler())
{ 
    // allow the bad certificate
    handler.ServerCertificateCustomValidationCallback = (request, cert, chain, errors) => true;
    using (var httpClient = new HttpClient(handler))
    {
        await httpClient.PostAsync("the_url", null);
    }
}

明确表示...

ServicePointManager.ServerCertificateValidationCallback += new System.Net.Security.RemoteCertificateValidationCallback(CertCheck);

private static bool CertCheck(object sender, X509Certificate cert,
X509Chain chain, System.Net.Security.SslPolicyErrors error)
{
    return true;
}

除了Sani和blak3r的答案外，我还在我的应用程序的启动代码中添加了以下内容，但在VB中：

'** Overriding the certificate validation check.
Net.ServicePointManager.ServerCertificateValidationCallback = Function(sender, certificate, chain, sslPolicyErrors) True

似乎可以解决问题。

提示：您还可以使用此方法来跟踪即将到期的证书。如果您发现即将过期的证书，并且可以及时进行修复，则可以节省培根。对第三方公司也很有利-对我们来说这是DHL / FedEx。DHL只是让证书过期，这让我们在感恩节前三天搞砸了。幸运的是，这次我要修复它！

    private static DateTime? _nextCertWarning;
    private static bool ValidateRemoteCertificate(object sender, X509Certificate cert, X509Chain chain, SslPolicyErrors error)
    {
        if (error == SslPolicyErrors.None)
        {
            var cert2 = cert as X509Certificate2;
            if (cert2 != null)
            { 
                // If cert expires within 2 days send an alert every 2 hours
                if (cert2.NotAfter.AddDays(-2) < DateTime.Now)
                {
                    if (_nextCertWarning == null || _nextCertWarning < DateTime.Now)
                    {
                        _nextCertWarning = DateTime.Now.AddHours(2);

                        ProwlUtil.StepReached("CERT EXPIRING WITHIN 2 DAYS " + cert, cert.GetCertHashString());   // this is my own function
                    }
                }
            }

            return true;
        }
        else
        {
            switch (cert.GetCertHashString())
            {
                // Machine certs - SELF SIGNED
                case "066CF9CAD814DE2097D367F22D3A7E398B87C4D6":    

                    return true;

                default:
                    ProwlUtil.StepReached("UNTRUSTED CERT " + cert, cert.GetCertHashString());
                    return false;
            }
        }
    }

以上工作有几个答案。我想要一种不必不断更改代码且不会使我的代码不安全的方法。因此，我创建了一个白名单。白名单可以在任何数据存储中维护。我使用配置文件，因为它是一个很小的列表。

我的代码如下。

ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, error) => {
    return error == System.Net.Security.SslPolicyErrors.None || certificateWhitelist.Contains(cert.GetCertHashString());
};

此解决方案的Unity C＃版本：

void Awake()
{
    System.Net.ServicePointManager.ServerCertificateValidationCallback += ValidateCertification;
}

void OnDestroy()
{
    ServerCertificateValidationCallback = null;
}

public static bool ValidateCertification(object sender, X509Certificate certificate, X509Chain chain, System.Net.Security.SslPolicyErrors sslPolicyErrors)
{
    return true;
}